Coffee maker



a- 15, 3 c. F. scoTT 2,159,852

' COFFEE MAKER Filed Sept. 10, 1937 I58. 20 K v Inventor: Carl F Scott 10 ra aX/ML His Attorne 9.

Patented Aug. 15, 1939 PATENT OFFICE COFFEE MAKER 1 Carl F. Scott, Milford, Coma, minor to General Electric Company, I corporation of New York Application September 10, 1937, Serial No. 163,280

BOlaims.

' This invention relates to coifee makers, and it v has for its object the provision of an improved device of this character.

This invention contemplates an improved coffee maker which heats the water to the proper temperature, and brings it into contact with the cofiee grounds under such conditions that a coffee brew is produced having an excellent flavor, and one that is free from coffee grounds. More specifically, this invention relates to improvements in the coffee maker described and claimed in the copending application of Roderick S. Mc- Neil, Serial No. 166,313, filed September 29, 1937, and assigned to the same assignee as this invention. It is an object of this invention to provide a coflee maker of the type described in the McNeil application which will automatically measure and make a relatively small number of cups of cofiee at a time, but which is adapted to make the maximum amount of coflee for which the cofiee maker is designed.

For a more complete understanding of this invention, reference should be had to the accompanying drawing in which Fig. 1 is an elevation mainly in section of acofiee maker embodying this invention; and Fig. 2 is a plan view of an electric hot plate for heating the coflee maker of Fig. 1- and arranged in accordance with this invention.

Referring to the drawing, this invention has been shown in one form as applied to a coffee maker operating on the principle set forth in the above-mentioned McNeil application. As shown, the-cofiee maker comprises a compartment in 5 which is adapted to receive the coffee grounds to be steeped or infused. This compartment or container I 0 is provided with a top opening ll through which the coflee grounds are inserted. This opening normally is closed by a cover 12. A

water heating vessel i3 is in liquid communication with the ground coffee receptacle it by means of a water delivery tube H. In accordance with the McNeil cofiee maker, thewater that is heated in the vessel I3 is transferred through the tube l4 to the ground coflee container ill by the generation of pressure in the vessel I3, the water that is transferred steeping or infusing the grounds in the vessel It. The coffee brew that is formed by the steeping of the grounds is discharged from the coffee compartment l0 through a discharge port ii that communicates with a depending discharge spout it. A screen dam I1 is positioned before the port having a mesh so fine that it sets up a back pressure in the compartment ll. That is, it

offers a resistance to the flow of the coii'ee grounds and brew from the coifee compartment. As pointed out in the McNeil application, this screen should have a rather fine mesh, such as approximately 200 per square inch.

In accordance with this invention, there is interposed between the ground coffee compartment I0 and the water heating compartment l3 a water reservoir i8. As shown, the three compartments are arranged one above the other. Preferably, the compartments will be enclosed by an outer relatively large cylindrical vessel It, and they will be defined by transverse partitions 20 and 2! arranged horizontally and spaced one above the other as shown in the drawing. Entering the side wall of the vessel IE to discharge into the reservoir I8 is a filler pipe lBa normally closed by a stopper lb.

The reservoir I8 is relatively large as compared with the proportions of the water heating vessel l3 and the ground coffee compartment Ill. The volumes of the latter two compartments III and I3 are substantially equal, although this is not necessary. The volume of the water reservoir l8 issuch that it will make a relatively la rge number of cups of coffee such as six or eight. The volume of the water heating compartment I3 is such that it will hold only enough water to make say two or three cups of cofiee.

Arranged in the wall 2i between the water heating compartment I3 and the reservoir I8 is a port 22 connecting these compartments. The port 22 .is controlled by meansof a valve 23 mounted on a rod 24. The rod 24 extends downwardly into the lower heating compartment l3 and upwardly through the top wall of compartment Ill to the top of the coffee maker, as shown. A tubular member 25 extends vertically from the bottom to the top wall of the coffee compartment ill and the rod 24 extends through this tube, as shown.

Positioned within the water heating compartment i3 is a float 26 surrounding the portion of the rod 24 that projects down into the heating chamber. When the valve 23 is open and water flows down into the chamber I 3 the float rises and eventually engages a shoulder 21 provided on the rod 24 and'upon continued movement upwardly will eventually close the valve. This occurs when a predetermined quantity of water has been supplied to the compartment i3. In other words, the float automatically operates to close the. valve when the desired measured quantity of water has been supplied to the compartment l3. Preferably, the valve 22 will be closed beforethechamber lliscompletelyfllledsoasto leave an air space above the liquid level. The maximum liquid level in compartment I8 is indicated by the line A.

when heat is applied to the compartment II. the water in it is heated as described before and the pressure that ultimately is generated due to vapor and the heating of air above the liquid level A will force the small quantity of water up through the tube l4 into the coffee steeping compartment II. The charge is pumped out rapidly and as the water is forced out. the float 28 drops to permit the valve 28 to again supply a charge or water to the heating compartment It. This charge is again heated and transferred to the coifee compartment III to make another batch of coffee brew. It is preferable that the valve 22 remain-closed until most of the water in the chamber It has been pump out. To effect this, a suitable locking member 21a is pivoted in the compartment I! under the rod 24. It is biased by its horizontal arm to occupy its position-shown in Fig. 1 where it holdsthe valve closed. As the float 2 8 approaches the bottom of the vessel ll, its inclined wall 26a engages the member 21a to move it in a counter-clockwise direction against its bias to release the rod 24 and thereby permit the valve 23 to open.

The foregoing construction has the advantage that a small quantity of coffee brew equalling approximately the volume of the water heating compartment It may be quickly made. The remaining charge of water may be converted into coifee brew in succeeding charges by permitting the valve 23 to repeatedly operate whereby successive charges of water are heated in chamber is and pumped through the brew compartment Ill.

Means are provided for holding the valve 21 open against the action of the float so that the maximum quantity of coifee may be made quickly.

For this purpose, the rod 24 at the top passes freely through a wing nut 21b. The nut when turned inwardly engages a shoulder 210 on the rod forcing it downwardly into a complementary seat. This operation forces the valve 23 open and holds it open. when the valve is thus held open, the steam generated will collect in the top of reservoir l8 and will force the entire water supply up through the tube l4 into the brew compartment ll.

Preferably, the wall 2| will be beat insulated. For this purpose, it may be provided with a double wall section Na and 2th spaced apart to define an air space He between them. This has the advantage that substantially all of the heat which is supplied'to the coflee maker will be used in heating up the relatively small quantity of water in the chamber if, very little of the heat flowing through the wall 2| to the water in the reservoir l8.

As shown, an electric hot plate 30 is provided to heat the water in the compartment ii. The hot plate 30 comprises a frame 3!, which preferably will be made of metal, housing an insulating brick 32 which is provided with a spiral channel 33. The heating resistance 34 is threaded through this. channel, as shown. The heating resistance 24 is controlled by means of a thermostatic switch 35' comprising a bimetallic thermostatic member 36 positioned adjacent the outer wall of the heating compartment II, as shown. This blade carries a switch contact 31 which cooperates with a second contact 38 mounted on a spring contact arm 39., The bimetallic strip 36 and the switch arm}! are electrically connected in the circuit of the hot plate, as shown, so that when the switch contacts are closed the heating resistance 84 is thermostat will open the heating circuit of the hot plate when the wall attains this temperature.

The hot plate is provided with an extension 4. constituting a platform or support for a vessel 4! to support the vessel in position where it will receive the coffee brew from the discharge spout ll of the coifee compartment. The platform 40 also preferably will be formed of metal and preferably will be a continuation of the frame 3| so that some heat will be transmitted by conduction from the frame II to the platform 40 to keep the coffee brew of the vessel 4| warm after the brew has been discharged into the vessel. The platform 40 may be made as a separate member and attached to the frame II in any suitable manner, as by screw fastening means. Preferably, the hot plate and platform will be provided with supporting feet 42.

While I have shown a a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

-1. A coffee maker and the like comprising a water chamber, a water heating chamber, a coffee compartment in liquid communication with said heating chamber so that when the water in said heating chamber has been heated sufllciently it is forced into said coffee compartment by the generation of pressure in the heating chamber, a valve controlling the flow of water from the water chamber to the heating chamber, means locking said valve in its closed position, and means responsive to the water level in said heating chamber operating to release said locking means to open said valve when the water level in said heating chamber has fallen to a predetermined low limit, and operating to move said valve to its closed position when a predetermined quantity of water has passed into said heating chamber.

2. A coffee maker comprising two vessels positioned one above the other, the higher being relatively large and constituting a water reservoir and the lower a water heating chamber, a port connecting said chambers, means for heating the water in the lower chamber, a ground coffee container in liquid connection with the lower chamber so that when the water in the lower chamber has been heated sufficiently it is transferred by pressure generated therein to the coflfee container to steep the coffee grounds and make a coffee brew, a valve controlling the flow of water from the upper to the lower chamher, a float operating to close said valve when a predetermined quantity of water has been supplied to the lower chamber, means locking said valve in its closed position, and said float operating said locking means to release said valve when the float falls to a predetermined low water level in said water. heating chamber.

3. A coflee maker comprising two vessels positioned one above the other, the higher constituting a water reservoir and the lower a water heating chamber, a port connecting said chambers, means for heating the water in the-lower cham- 6 her, a ground coffee container in liquid conm'iunication with the lower'chamber so that when the water in the lower chamber has been heated sufficiently it is transferred by pressure generated therein'to the cofl'ee container to steep the cof- 10 fee grounds and make a coffee brew, a valve controlling the flow of water from the upper to the lower chamber, a float operating to close said valve when a predetermined quantity of water has been supplied to the lower chamber, and 15 means controlling the operation of said valve independently of the position of said float.

4. A cofiee maker comprising two vessels positioned one above the other, the higher constituting a water reservoir and the lower a water heat- 20 ing chamber, a port connecting said chambers,

means for heating the water in the lower chamber, a ground cofiee container in liquid communication with the lower chamber so that when the water in the lower chamber has been heated sum- 25 ciently it is transferred by pressure generated in the chamber to the coifee container to steep the cofiee grounds and make a coffee brew, the coffee container having a port discharging therefrom to permit the coffee brew that has been made 30 to flow from the container, a screen dam over said port opposing the flow of the brew from the container, a valve controlling the flow of water from the upper to the lower chamber, a float operat- 35 ing to close said valve when said lower chamber has been substantially filled, the lower chamber being proportioned so that a maximum of but a relatively few cups of coffee brew can be made at a time, and means controlling said valve so that it may be held open independently of the position of said float.

5. A coffee maker comprising walls defining three vessels positioned vertically one above the other, the top vessel constituting a ground coffee receptacle, the center a water reservoir and the lower a water heating chamber, a water delivering tube connecting the latter with the top vessel, a delivery port between the reservoir and the heating chamber, a float operated valve controlling said port to close the port when a predetermined quantity of water has been supplied to the heating chamber, means locking said valve in its closed position, and said float operating said locking means to release said valve when the float falls to a predetermined low water level in said water heating chamber.

6. A coifee maker comprising walls defining three vessels positioned vertically one above the other, the top vessel constituting a ground coffee receptacle, the center a water reservoir and the lower a water heating chamber, a water delivery tube connecting the latter with the top vessel, a delivery port between the reservoir and the heating chamber, a float operated valve controlling said port to close the port when a predetermined quantity of water has been supplied to the heating chamber, and the top vessel having a discharge port for the cofiee brew, an electric hot plate for heating and supporting said vessels so as to heat the water in the heating chamber, the hot plate having a laterally positioned supporting platform in heat conducting relation with the plate, the platform serving to support a portable vessel placed upon it, and the ground cofiee receptacle having a spout adapted to discharge into said vessel when placed on the platform.

' CARL F. SCO'I'I. 

